$re = '/\$\d+(?![0-9.])/m';
$str = '5x Item C $2.5x5, $2.50x1
1 Book $2.55
1x Table $2.59
2x Item A $2000.5x2, 10x Item B $0.5x10
1x Test $2.513, 5x Pear $100x5
$1.430
$1.50
$1.55
10x Tee $0.5x10
50x SSS $6.5x50
$2.5, $50';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php